This reverts commit 0ba115e6.

Reason for revert: Breaks test on TSAN - block-conflicts
https://ci.chromium.org/p/v8/builders/ci/V8%20Linux64%20TSAN%20-%20concurrent%20marking/14230

Original change's description:
> Reland^2 "[flags] warn about contradictory flags"
> 
> This is a reland of d8f8a7e2
> Change compared to last reland:
> - Do not check for d8 flag contradictions in the presence of --fuzzing
> - Allow identical re-declaration of --cache=*
> 
> Original change's description:
> > Reland "[flags] warn about contradictory flags"
> >
> > This is a reland of b8f91666
> > Difference to previous CL: Additional functionality to specify
> > incompatible flags based on GN variables and extra-flags, used
> > to fix the issues that came up on the waterfall.
> >
> > This also changes the rules regarding repeated flags: While
> > explicitly repeated flags are allowed for boolean values as long
> > as they are identical, repeated flags or explicit flags in the
> > presence of an active implication are disallowed for non-boolean
> > flags. The latter simplifies specifying conflict rules in
> > variants.py. Otherwise a rule like
> >
> > INCOMPATIBLE_FLAGS_PER_EXTRA_FLAG = {
> >   "--gc-interval=*": ["--gc-interval=*"],
> > }
> >
> > wouldn't work because specifying the same GC interval twice
> > wouldn't actually count as a conflict. This was an issue with
> > test/mjsunit/wasm/gc-buffer.js, which specifies
> > --gc-interval=500 exactly like the extra flag by the stress bot.
> >
> > Also, this now expands contradictory flags checking to d8 flags
> > for consistency.
> >
> > Original change's description:
> > > [flags] warn about contradictory flags
> > >
> > > Design Doc: https://docs.google.com/document/d/1lkvu8crkK7Ei39qjkPCFijpNyxWXsOktG9GB-7K34jM/
> > >
> > > Bug: v8:10577
> > > Change-Id: Ib9cfdffa401c48c895bf31caed5ee03545beddab
> > > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2154792
> > > Reviewed-by: Clemens Backes <clemensb@chromium.org>
> > > Reviewed-by: Michael Achenbach <machenbach@chromium.org>
> > > Reviewed-by: Georg Neis <neis@chromium.org>
> > > Reviewed-by: Tamer Tas <tmrts@chromium.org>
> > > Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
> > > Cr-Commit-Position: refs/heads/master@{#68168}
> >
> > Bug: v8:10577
> > Change-Id: I268e590ee18a535b13dee14eeb15ddd0a9ee8341
> > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2235115
> > Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
> > Reviewed-by: Tamer Tas <tmrts@chromium.org>
> > Reviewed-by: Clemens Backes <clemensb@chromium.org>
> > Reviewed-by: Georg Neis <neis@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#68989}
> 
> Bug: v8:10577
> Change-Id: I31d2794d4f9ff630f3444210100c64d67d881276
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2339464
> Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
> Reviewed-by: Clemens Backes <clemensb@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#69339}

TBR=machenbach@chromium.org,neis@chromium.org,clemensb@chromium.org,tebbi@chromium.org,tmrts@chromium.org

Change-Id: I1454a05e357ddd704db7fb79e51be65d45a9a16e
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:10577
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2348365Reviewed-by: Bill Budge <bbudge@chromium.org>
Commit-Queue: Bill Budge <bbudge@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69341}